Telephone Line Powered LED Lamp
This small and bright LED lamp is telephone line powered, means it uses the power of our telephone line. There are about -40v to -50v at telephone line, LM317T is used to adjust them according to our demand.
12 white LEDs of 5mm dia is used in this lamp, are all in series to compensate the voltage. Out of four wires of telephone only red and green is of our interest. This telephone line powered LED lamp is small, efficient and bright; one can also be use this for study or desk lamp. |
Schematic:
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| Telephone Line Operated LED Lamp |
Components Required:
BR2----------------------Bridge Rectifire
U2------------------------LM617T or LM317L
R3-------------------------270 ohm 1/2watt
R4-------------------------6.8k ohm
12 white LEDs
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